ertiary secondary settlement). The material used as adsorbent could

ertiary treatment can be used when the effluent from the secondary treatment does not meet the increased in standards for recreational, domestic and industrial requirement on the receiving of wastewater. This treatment can be adopted to further reduce the solids and organic content of the effluent. The major substances that need to be removed are nitrogen and phosphorus. This will cause expansion of planktonic algae in the water which will affect the environment. The detention time can be increased so as to allow greater removals. By going through the tertiary treatment, it reduces the concentration of nitrogen and phosphorus at 55% and 40% respectively.A physicochemical treatment is adsorption where it is process of retention on the surface of an element (solid or liquid) of molecules of other substances (in the wastewater, it refers to the fine particles in suspension which remained in wastewater after the secondary settlement). The material used as adsorbent could be activated carbon. Activated carbon has a high specific surface area and a highly developed pore structure, so it is characterized by its function on absorbing dissolved oxygen and organics in raw water.A physical method used for tertiary treatment water are the passing through micro screeners or sand filters. The water will pass through the micro screener and the aim is to capture fine particles in suspension, which remained in the waste water after the secondary treatment. The sieve of a micro screener has a maximum size of 23um and its surface is fixed fine particles that determine the retention of other particles smaller than the mesh of the micro screener. Nevertheless, the use of a micro screener is not advisable when the waste water is full of large quantities of colloid or variable composition. Another possible choice is the sand filtration system. Moreover, the sand filtration is more efficient and cheaper than use of micro screeners, however, sand filtration produces a decrease of dissolved oxygen in water treated and oxygen is a necessity in aeration (L.M. Boeriui, .L. Cirstolovean, M. Fratu, C. Nastac,2013 )